PGC-1α and myokines in the aging muscle - a mini-review.

Aging is associated with far-reaching changes in physiological functions resulting in morbidity and ultimately death. Age-related frailty, insecurity and reduced physical activity contribute to a progressive loss of muscle mass and function, commonly referred to as sarcopenia. Due to the increase in life expectancy in many countries, loss of muscle mass and its consequences gain in relevance for public health. At the same time, the molecular mechanisms that underlie sarcopenia are poorly understood and therefore, therapeutic approaches are limited. Interestingly though, endurance, strength and stretching exercise is significantly superior to all known pharmacological, nutritional and hormonal interventions for stabilizing, alleviating and reversing sarcopenia. Thus, increased knowledge about the plastic changes of skeletal muscle after physical activity and the signaling factors that mediate the beneficial effects of exercise on other organs might yield a better understanding of the disease and open new avenues for treatment. Here, we discuss how current discoveries about the peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), a key exercise factor in muscle, and myokines, factors produced and secreted by active muscle fibers, expand our view of the pathological changes and the therapeutic options for sarcopenia.